<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
       .contain {
			position: relative;
			width: 200px;
			height: 200px;
		}
		.main {
			height: 100%;
			background: lightgreen;
			border-radius: 100px;
		}
		.common {
			position: absolute;
			top: 0;
			width: 50%;
			height: 100%;
		}
		.mask1 {
			transform: rotate(83deg);
			border-radius: 100px 0 0 100px;
			left: 0;
			transform-origin: right center;
			background: red;
		}
		.mask2 {
			transform: rotate(-76deg);
			transform-origin: left center;
			left: 100px;
			border-radius: 0 100px 100px 0;
			background: blue;
		}
  </style>
</head>
<body>
  <!-- [css] 用CSS画出一个任意角度的扇形，可以写多种实现的方法 -->
  <div class="contain">
		<div class="main"></div>
		<div class="mask1 common"></div>
		<div class="mask2 common"></div>
	</div>
</body>

</html>